Does lamotrigine use in pregnancy increase orofacial cleft risk relative to other malformations?

OBJECTIVE: To investigate whether first trimester exposure to lamotrigine (LTG) monotherapy is specifically associated with an increased risk of orofacial clefts (OCs) relative to other malformations, in response to a signal regarding increased OC risk. METHODS: Population-based case-control study with malformed controls based on EUROCAT congenital anomaly registers. The study population covered 3.9 million births from 19 registries 1995-2005. Registrations included congenital anomaly among livebirths, stillbirths, and terminations of pregnancy following prenatal diagnosis. Cases were 5,511 nonsyndromic OC registrations, of whom 4,571 were isolated, 1,969 were cleft palate (CP), and 1,532 were isolated CP. Controls were 80,052 nonchromosomal, non-OC registrations. We compared first trimester LTG and antiepileptic drug (AED) use vs nonepileptic non-AED use, for mono and polytherapy, adjusting for maternal age. An additional exploratory analysis compared the observed and expected distribution of malformation types associated with LTG use. RESULTS: There were 72 LTG exposed (40 mono- and 32 polytherapy) registrations. The ORs for LTG monotherapy vs no AED use were 0.67 (95% CI 0.10-2.34) for OC relative to other malformations, 0.80 (95% CI 0.11-2.85) for isolated OC, 0.79 (95% CI 0.03-4.35) for CP, and 1.01 (95% CI 0.03-5.57) for isolated CP. ORs for any AED use vs no AED use were 1.43 (95% CI 1.03-1.93) for OC, 1.21 (95% CI 0.82-1.72) for isolated OC, 2.37 (95% CI 1.54-3.43) for CP, and 1.86 (95% CI 1.07-2.94) for isolated CP. The distribution of other nonchromosomal malformation types with LTG exposure was similar to non-AED exposed. CONCLUSION: We find no evidence of a specific increased risk of isolated orofacial clefts relative to other malformations due to lamotrigine (LTG) monotherapy. Our study is not designed to assess whether there is a generalized increased risk of malformations with LTG exposure.

Drug prescription patterns before, during and after pregnancy for chronic, occasional and pregnancy-related drugs in the Netherlands.

OBJECTIVE: To compare the prescription of drugs in women over a period from 2 years before until 3 months after pregnancy, regarding the type of drugs used and the fetal risk. DESIGN: A cohort study based on pharmacy records of women giving birth to a child between 1994 and 2003. SETTING: The study was performed with data from the InterAction database, containing prescription-drug-dispensing data from community pharmacies. POPULATION: The study population included 5412 women for whom complete pharmacy records were available. METHODS: Drugs were classified into three categories: (1) drugs for chronic conditions, (2) drugs for occasional use and (3) drugs for pregnancy-related symptoms and also classified according to the Australian classification system. MAIN OUTCOME MEASURES: The prescription rate was calculated as the number of women per 100 women who received one or more prescriptions for a given drug within a specified time period. RESULTS: About 79.1% of the women received at least one prescription during pregnancy. The prescription rate for most drugs for chronic diseases and for occasional use decreased during pregnancy, whereas, as expected, the prescription rate for pregnancy-related drugs increased. During the first trimester of pregnancy, 1.7% of all drugs prescribed for chronic conditions and 2.3% of the occasional drugs were classified as harmful. CONCLUSIONS: The increase in prescription rate during pregnancy is caused by an increase in prescription rate of drugs for pregnancy-related symptoms. The prescription of harmful drugs is more commonly associated with drugs for occasional use rather than with drugs for chronic conditions. Therefore, a more cautious prescribing of drugs to healthy women in the fertile age is necessary.